UNIVERSITI PUTRA MALAYSIA

UTILIZATION OF BIOMASS-DERIVED ACTIVATED CARBON AS CATALYST SUPPORT AND BIOADSORBENT IN BIODIESEL

PRODUCTION USING WASTE COOKING OIL AS FEEDSTOCK

MOHAMMED ABDILLAH BIN AHMAD FARID

FBSB 2017 14

© COPYRIG

HT UPMUTILIZATION OF BIOMASS-DERIVED ACTIVATED CARBON AS

CATALYST SUPPORT AND BIOADSORBENT IN BIODIESEL PRODUCTION USING WASTE COOKING OIL AS FEEDSTOCK

By

MOHAMMED ABDILLAH BIN AHMAD FARID

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirement for Degree of Master of Science

April 2017

© COPYRIG

HT UPM

All material contained within the thesis, including without limitation text, logos, icons, photographs and all other artwork, is copyright material of Universiti Putra Malaysia unless otherwise stated. Use may be made of any material contained within the thesis for non-commercial purposes from the copyright holder. Commercial use of material may only be made with the express, prior, written permission of Universiti Putra Malaysia.

Copyright © Universiti Putra Malaysia

© COPYRIG

HT UPM

i

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

UTILIZATION OF BIOMASS-DERIVED ACTIVATED CARBON AS CATALYST SUPPORT AND BIOADSORBENT IN BIODIESEL

PRODUCTION USING WASTE COOKING OIL AS FEEDSTOCK

By

MOHAMMED ABDILLAH BIN AHMAD FARID

April 2017

Supervisor : Mohd Ali Hassan, PhD Faculty : Biotechnology and Biomolecular Sciences

The depletion of non-renewable fossil fuels and the growing environmental awareness, biodiesel is seen as a promising substitute for the conventional diesel. Its eco-friendly properties such as being renewable, biodegradable and less carbon emission have brought new hope for a greener future. Presently, waste cooking oil and oil palm empty fruit bunch were extensively used as the raw materials for a low-cost feedstock and catalyst for biodiesel production. Apart from its economic objective, exploitation of these abundant waste sources for biodiesel production is a step ahead in saving the environment from pollution, as it is typically being disposed indiscriminately.

In this study, improved production of biodiesel from waste cooking oil was achieved by using a newly developed potassium phosphate tri-basic supported activated carbon catalyst. In order to produce high surface area activated carbon, press-shredded oil palm empty fruit bunch was subjected to carbonization at 700ᴼC for 2 h followed by activation with potassium hydroxide at 700ᴼC for 2 h. To produce the catalyst, calcination was performed at different potassium phosphate tri-basic impregnation concentrations (1:0.25 to 1:1 activated carbon to potassium phosphate tri-basic weight ratio) and temperatures (400ᴼC to 700ᴼC). Prior to transesterification, waste cooking oil was analysed for its physicochemical properties and pre-treated to remove moisture and residues. Under the optimum condition of 5 wt% catalyst loading, 12:1 methanol to oil molar ratio at 60ᴼC for 4 h, 98% of biodiesel yield was achieved, which surpassed the European Biodiesel Standard (EN 14214). The catalyst was reusable for 5 successive reaction cycles, achieving almost 80% of biodiesel yield.

© COPYRIG

HT UPM

ii

In addition, the activated carbon produced from the press-shredded oil palm empty fruit bunch was also utilized as bioadsorbent to remove impurities from the crude biodiesel. The purification process was performed using different adsorbent loadings (1 to 5 wt%) under continuous stirring condition at 500 rpm for 1 h. Approximately 89.71% of methanol, 81.74% of water, 36.67% of FFA and 98.61% of potassium (K) were successfully removed after purification at 5 wt% of bioadsorbent loading, which met the European Biodiesel Standards (EN 14214). In comparison to other commercial adsorbents and conventional water washing method, purification using the biomass-derived bioadsorbent resulted in better removal of methanol, water and triglyceride impurities with only a small loss of biodiesel yield.

© COPYRIG

HT UPM

iii

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

PENGGUNAAN KARBON TERAKTIF DIPEROLEH DARIPADA BIOJISIM SEBAGAI PENYOKONG PEMANGKIN DAN BIO-PENJERAP DIDALAM PENGHASILAN BIODIESEL MENGGUNAKAN SISA MINYAK MASAK

SEBAGAI BAHAN MENTAH

Oleh

MOHAMMED ABDILLAH BIN AHMAD FARID

April 2017

Penyelia : Mohd Ali Hassan, PhD Fakulti : Bioteknologi dan Sains Biomolekul

Dengan pengurangan bahan api fosil yang tidak boleh diperbaharui dan kesedaran alam sekitar yang semakin meningkat, biodiesel dilihat sebagai pengganti yang memberangsangkan untuk diesel konvensional. Ciri-ciri mesra alam seperti boleh diperbaharui, biodegradasi dan kurang pelepasan karbon telah membawa harapan baru untuk masa depan yang lebih hijau. Kini, sisa minyak masak telah digunakan dengan meluas sebagai bahan mentah dan pemangkin bagi pengeluaran biodiesel kos rendah. Selain daripada objektif ekonomi, eksploitasi sumber sisa yang banyak ini bagi pengeluaran biodiesel adalah satu langkah ke hadapan dalam menyelamatkan alam sekitar daripada pencemaran dan penyumbatan sistem kumbahan sanitari, kerana ia biasanya dilupuskan secara sewenang-wenangnya.

Dalam kajian ini, peningkatan pengeluaran biodiesel daripada sisa minyak masak telah dicapai dengan menggunakan pemangkin potassium fosfat tri-asas disokong karbon teraktif. Dalam usaha untuk menghasilkan luas permukaan karbon teraktif yang tinggi, tandan kelapa sawit kosong ditekan-cincang telah dikarbonisasi pada suhu 700ᴼCselama 2 jam diikuti oleh pengaktifan dengan kalium hidroksida pada 700ᴼC selama 2 jam. Pengkalsinan dilakukan pada kepekatan impregnasi kalium fosfat tri-asas (1: 0.25 kepada 1: 1 diaktifkan karbon kalium fosfat nisbah berat tri-asas kepada) dan suhu (400ᴼC untuk 700ᴼC) yang berbeza. Sebelum transesterifikasi, sifat fizikokimia sisa minyak masak telah dianalisis dan dipra-rawat untuk membuang kelembapan dan residu. Di bawah keadaan optimum 5% berat unit muatan pemangkin, 12:1 nisbah

© COPYRIG

HT UPM

iv

molar metanol kepada sisa minyak masak pada 60ᴼC untuk bagi 4 jam, 98% hasil biodiesel telah dicapai, yang melepasi Piawaian Biodiesel Eropah (EN 14214). Pemangkin ini boleh diguna semula untuk 5 kitaran reaksi berturut-turut, mencapai hampir 80% hasil biodiesel.

Di samping itu, karbon teraktif yang dihasilkan daripada tandan kelapa sawit kosong yang ditekan-cincang juga digunakan sebagai bio-penjerap untuk membuang kekotoran daripada biodiesel mentah seperti air, asid lemak bebas (FFA), metanol, gliserin bebas, trigliserida dan kalium. Proses penulenan biodiesel mentah yang dihasilkan daripada sisa minyak masak telah dilakukan dengan menggunakan muatan penjerap yang berbeza (1 hingga 5% berat unit) di bawah keadaan kacau berterusan pada 500 rpm selama 1 jam. Kira-kira 89.71% metanol, 81.74% air, 36.67% FFA and 98.6% kalium telah berjaya dibuang selepas penulenan pada 5% berat unit muatan bio-penjerap, yang mana telah melepasi Piawaian Biodiesel Eropah (EN 14214). Berbanding dengan penjerap komersial yang lain dan kaedah konventional basuhan air, penulenan menggunakan bio-penjerap yang diperolehi daripada biojisim telah mengakibatkan penyingkiran metanol, air dan trigliserida yang lebih baik dengan kehilangan hasil biodiesel yang kecil.

© COPYRIG

HT UPM

v

ACKNOWLEDGEMENTS

“In The Name of Allah, the Most Gracious and Most Merciful”

First of all, praise to ALLAH SWT for the opportunity given in facing all the difficulties during my research.

Words cannot express my gratitude towards my supervisor Prof. Dr. Mohd Ali Hassan, who has been my advisor for guidance in this thesis research. Also, I would like to heartily thank my co-supervisors Prof. Dr. Yoshihito Shirai and Prof. Dr. Taufiq Yap Yun Hin who gave me the knowledge, advice and generous suggestions throughout my research work.

To all other members of Biomass Technology Center lab, I would like to express my gratitude and thankfulness for creating such a friendly working atmosphere and all the useful discussions.

Finally, this special gratefulness goes to my parents and my siblings. This research work and thesis writing would not complete without their support and encouragement continuously from the beginning until the successful completion.

© COPYRIG

HT UPM

© COPYRIG

HT UPM

vii

This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfillment of the requirement for the degree of Master of Science. The members of the Supervisory Committee were as follows:

Mohd Ali Hassan, PhD Professor Faculty of Biotechnology and Biomolecular Sciences Universiti Putra Malaysia (Chairman)

Taufiq Yap Yun Hin, PhD Professor Faculty of Science, University Putra Malaysia (Member)

Yoshihito Shirai, PhD Professor Graduate School of Life Sciences and System Engineering Kyushu Institute of Technology (Member)

_________________________ ROBIAH BINTI YUNUS, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia

Date:

© COPYRIG

HT UPM

viii

Declaration by graduate student

I hereby confirm that:

� This thesis is my original work; � Quotations, illustrations and citations have been duly referenced; � This thesis has not been submitted previously or concurrently for any other degree

at any other institutions; � Intellectual property from the thesis and copyright of thesis are fully owned by

Universiti Putra Malaysia, as according to the Universiti Putra Malaysia (Research) Rules 2012;

� Written permission must be obtained from supervisor and the office of Deputy Vice-Chancellor (Research and Innovation) before thesis is published (in the form of written, printed or in electronic form) including books, journals, modules, proceedings, popular writings, seminar papers, manuscripts, posters, reports, lecture notes, learning modules or any other materials as stated in the Universiti Putra Malaysia (Research) Rules 2012;

� There is no plagiarism or data falsification/fabrication in the thesis, and scholarly integrity is upheld as according to the Universiti Putra Malaysia (Graduate Studies) Rules 2003 (Revision 2012-2013) and the Universiti Putra Malaysia (Research) Rules 2012. The thesis has undergone plagiarism detection software.

Signature: ____________________________ Date: _________________

Name and Matric No.: Mohammed Abdillah Bin Ahmad Farid (GS37941)

© COPYRIG

HT UPM

ix

Declaration by Members of Supervisory Committee

This is to confirm that:

� The research conducted and the writing of this thesis was under our supervision; � Supervision responsibilities as stated in the Universiti Putra Malaysia (Graduate

Studies) Rules 2003 (Revision 2012-2013) are adhered to.

Signature: ___________________________ Name of Chairman of Supervisory Committee: Prof. Dr. Mohd Ali Hassan

Signature: __________________________ Name of Member of Supervisory Committee: Prof. Dr. Taufiq Yap Yun Hin

Signature: __________________________ Name of Member of Supervisory Committee: Prof. Dr. Yoshihito Shirai

© COPYRIG

HT UPM

x

TABLE OF CONTENTSPage

ABSTRACT i

ABSTRAK iii

ACKNOWLEDGEMENTS v

APPROVAL vi

DECLARATION viii

LIST OF TABLES xiv

LIST OF FIGURES xv

LIST OF ABBREVATIONS xvii

CHAPTER

1 INTRODUCTION1.1 General introduction 1

1.2 Problem statement 1

1.3 Specific objectives 3

1.4 Experimental overview 3

2 LITERATURE REVIEW2.1 Oil palm biomass waste 5

2.1.1 Oil Palm Empty fruit bunch (OPEFB) 5

2.2 Activated carbon produced from oil palm empty fruit bunch (OPEFB)

6

2.3 Biodiesel 9

2.4 Biodiesel feedstocks 9

2.4.1 Waste cooking oil (WCO) 10

2.4.2 Properties of waste cooking oil (WCO) 10

2.5 Biodiesel production methods 11

2.5.1 Transesterification 11

2.5.2 Esterification 14

2.6 Variables affecting in biodiesel production 15

2.6.1 Reaction temperature 15

2.6.2 Reaction time 15

2.6.3 Molar ratio of alcohol to oil feedstock 15

2.6.4 Free fatty acid (FFA) 16

2.6.5 Moisture content 16

2.6.6 Types of catalyst 16

2.6.6.1 Homogeneous catalyst 18

2.6.6.2 Heterogeneous catalyst 20

© COPYRIG

HT UPM

xi

2.6.6.2.1 Carbon supported catalyst

21

2.7 Biodiesel Purification 25

2.7.1 Water-washing purification method 26

2.7.2 Dry purification using adsorbents 27

2.7.2.1 Biodiesel purification using activated carbon

28

2.7.2.2 Biodiesel purification using silica gel

28

2.7.2.3 Biodiesel purification using bentonite

29

2.7.2.4 Biodiesel purification using talc 29

2.8 Biodiesel Quality Standards 29

3 BIODIESEL PRODUCTION FROM WASTE COOKING OIL USING HETEROGENEOUS BIOMASS-BASED CATALYST3.1 Introduction 32

3.2 Materials and Methods 32

3.2.1 Materials 32

3.2.2 Characterization of waste cooking oil (WCO)

33

3.2.2.1 Molecular weight of waste cooking oil (WCO)

33

3.2.3 Catalyst preparation 34

3.2.4 Catalyst characterization 36

3.2.4.1 Scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX)

36

3.2.4.2 Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH)

37

3.2.4.3 Temperature Programmed Desorption of Carbon Dioxide (TPD-CO2)

37

3.2.4.4 X-ray diffraction (XRD) 38

3.2.4.5 Fourier transform infrared (FT-IR) spectroscopy

38

3.2.5 Preliminary treatment of oil feedstock 38

3.2.6 Transesterification 38

3.2.7 Catalyst reusability and leaching 40

3.3 Results and Discussion 40

3.3.1 Characterization of waste cooking oil (WCO)

40

© COPYRIG

HT UPM

xii

3.3.2 Characterization of catalyst 41

3.3.3 Transesterification reaction 46

3.3.3.1 Effect of calcination temperature

47

3.3.3.2 Effect of K3PO4 impregnation concentration

49

3.3.3.3 Effect of catalyst loading 50

3.3.3.4 Effect of methanol to oil molar ratio

50

3.3.3.5 Effect of temperature reaction 52

3.3.4 Reusability and leaching properties 53

3.4 Summary 55

4 UTILIZATION OF BIOMASS-DERIVED BIOADSORBENT IN THE PURIFICATION OF BIODIESEL PRODUCED FROM WASTE COOKING OIL4.1 Introduction 56

4.2 Materials and Methods 56

4.2.1 Materials 56

4.2.2 Molecular weight of waste cooking oil (WCO)

57

4.2.3 OPEFB-derived activated carbon production 57

4.2.4 Characterization of adsorbents 57

4.2.4.1 Scanning electron microscope (SEM)

57

4.2.4.2 Fourier transform infrared spectroscopy (FT-IR)

58

4.2.4.3 Brunauer-Emmet-Teller (BET) and energy-dispersive X-ray (EDX)

58

4.2.4.4 Methylene blue maximum adsorption capacity

58

4.2.5 Biodiesel production from waste cooking oil (WCO)

58

4.2.6 Correlation study between biodiesel impurities removal and bioadsorbent

59

4.2.7 Biodiesel purification using adsorbents 59

4.2.8 Biodiesel purification using conventional purification method

59

4.3 Results and Discussion 60

4.3.1 Characterization of crude biodiesel 60

4.3.2 Characterization of adsorbents 61

4.3.3 Correlation between adsorbent loading and biodiesel impurity removal

65

© COPYRIG

HT UPM

xiii

4.3.4 Comparison using OPEFB- derived activated carbon with other commercial adsorbents

68

4.3.5 Bioadsorbent versus water washing purification method

70

4.4 Summary 72

5 CONCLUSION AND RECOMMENDATIONS5.1 Conclusions 73

5.2 Recommendations 74

REFERENCES 75

APPENDICES 88

BIODATA OF STUDENT 96

LIST OF PUBLICATIONS 97

© COPYRIG

HT UPM

xiv

LIST OF TABLES

Table Page

2.1 Comparison of activated carbon production from oil palm empty fruit bunch (OPEFB)

8

2.2 Comparison of different technologies for biodiesel production

11

2.3 Homogeneous base catalysts 19

2.4 Homogeneous acid catalysts 20

2.5 Comparison of homogenously and heterogeneous catalyzed transesterification

21

2.6 Comparison of carbon supported acid catalysts 24

2.7 Effect of biodiesel impurities in engine 26

2.8 American standard specification for biodiesel (ASTM D6751)

30

2.9 European standard specifications for biodiesel (EN 14214)

31

3.1 Characterization of waste cooking oil (WCO) 41

3.2 Surface area, pore volume, average pore radius, basicity (TPD-CO2), and surface elemental distribution of OPEFB-derived activated carbon and K3PO4(1:0.25-1:1)/AC catalysts

44

3.3 FAME yield, potassium (K) and phosphorus (P) content of biodiesel product for 8 consecutive reaction cycles

54

4.1 Physicochemical properties of crude biodiesel produced from waste cooking oil (WCO)

60

4.2 Surface properties of adsorbents 63

4.3 Correlation between adsorbent loading and biodiesel impurity removal using OPEFB-derived activated carbon

66

4.4 Quality of biodiesel after purification using OPEFB-derived activated carbon and other commercial adsorbents

69

4.5 Quality of biodiesel after purification with water washing and OPEFB-derived activated carbon

71

© COPYRIG

HT UPM

xv

LIST OF FIGURES

Figure Page

1.1 Research work flow 4

2.1 Reaction equation of transesterification 12

2.2 Elaborate reaction equations for transesterification 12

2.3 Process flow diagram involved in biodiesel production 13

2.4 Reaction equation between alkaline catalyst and FFA 14

2.5 Reaction between acid catalyst and FFA 15

2.6 Types of catalyst for biodiesel production 17

2.7The conventional impregnation of aqueous solution between catalyst on carbon support material

23

3.1 Ground press-shredded oil palm empty fruit bunch (OPEFB) 35

3.2 Furnace equipped with nitrogen gas inlet 35

3.3 OPEFB-derived activated carbon 36

3.4One litre three-neck round-bottom flask digital heating mantle equipped with magnetic stirring and reflux condenser

39

3.5

Scanning electron micrographs of (A) K3PO4(1:1)/AC (view of capillary pores); (B) K3PO4(1:1)/AC (view of outer surface); (C) K3PO4(1:0.25)/AC (view of capillary pores); (D) K3PO4(1:0.25)/AC (view of outer surface); (E) OPEFB-derived activated carbon (view of capillary pores); and (F) OPEFB-derived activated carbon (view of outer surface)

42

3.6XRD diffractogram of OPEFB-activated carbon, K3PO4, and K3PO4(1:0.25-1:1)/AC catalysts

45

3.7FTIR spectra of OPEFB-activated carbon and K3PO4(1:0.25 -

1:1)/AC catalysts46

3.8 Thermogravimetric analysis (TGA) for the impregnated sample 48

3.9Biodiesel yield using K3PO4(1:0.75)/AC at different calcination temperatures

48

© COPYRIG

HT UPM

xvi

3.10Effect of K3PO4 impregnation concentration (weight ratio of OPEFB-derived activated carbon to K3PO4 of 1:0.25 to 1:1) on biodiesel production from waste cooking oil (WCO)

49

3.11Effect of catalyst loading on biodiesel production from waste cooking oil (WCO)

50

3.12Effect of methanol to oil molar ratio on biodiesel productionfrom waste cooking oil (WCO)

51

3.13Effect of reaction temperature on biodiesel production from waste cooking oil (WCO)

52

3.14Reusability of the catalyst for 8 consecutive reaction cycles in biodiesel production from waste cooking oil (WCO)

54

4.1SEM micrographs at 300X magnification: (A) bentonite; (B) silica gel; (C) talc; and (D) OPEFB-derived activated carbon

62

4.2FT-IR spectrum of adsorbents: (A) talc; (B) silica gel; (C) OPEFB-derived activated carbon; and (D) bentonite

64

4.3Removal percentage of biodiesel impurities after purification with OPEFB-derived activated carbon at ranging adsorbent loading

67

4.4Removal percentage of biodiesel impurities after purification using OPEFB-derived activated carbon and other commercial adsorbents

69

4.5Removal percentage of biodiesel impurities after purification using conventional water washing method and OPEFB-derived activated carbon

71

© COPYRIG

HT UPM

xvii

LIST OF ABBREVIATIONS

ASTM D6751 American biodiesel standard

BET Brunauer–Emmett–Teller

BJH Barrett-Joyner-Halenda

CH3OH Methanol

CO2 Carbon dioxide

Cu Copper

EN14214 European biodiesel standard

EDX Energy-dispersive X-ray

FAME Fatty acids methyl esters

FELDA Federal Land Development Authority

FTIR Fourier transform infrared spectroscopy

FFA Free fatty acids

GC Gas Chromatography

He Helium gas

h Hour

H2 Hydrogen gas

HCl Hydrochloride acid

K Potassium

KBr Potassium bromide

KOH Potassium hydroxide

K3PO4 Potassium phosphate tri-basic

MB Methylene blue

min Minute

M Molar

© COPYRIG

HT UPM

xviii

N2 Nitrogen gas

OPEFB Oil palm empty fruit bunch

P Phosphorus

rpm Rotation per minute

SEM Scanning electron microscope

TPD Temperature Programmed Desorption

XRD X-ray Diffraction

© COPYRIG

HT UPM

1

CHAPTER 1

INTRODUCTION

1.1 General introduction

It has been two centuries since petroleum was found and now almost 90 % of world energy supplies relied on fossil fuels (Chew & Bhatia, 2008). Nevertheless, due to its growing demand and uncontrollable consumption, the earth has begun to bear the negative consequences such as depletion of fossil fuel reserves and climate change (Adam et al., 2011). Based on the current estimate, it was expected that world fossil fuel reserves could only last for another 53 years (Xu et al., 2016). Undisputedly, the upsurge in fossil fuels utilization has increased the amount of CO2 emission which leads to global warming (Yusuf et al., 2011). Therefore, the scientific community has been intensively conducting studies to seek solutions for these issues.

Biodiesel is one of the potential biofuels that could reduce our energy dependency on fossil fuels. It consists of long-chain fatty acid alkyl esters and are normally produced from agricultural oils which are renewable (Berrios et al., 2010). It has been regarded as an alternative towards the petroleum diesel due to its better features such as low carbon emission, greater lubricity, biodegradable and less toxic (Dehkhoda et al.,2010).

1.2 Problem statement

With current technologies implemented, biodiesel production process is cost-ineffective. High price of feedstocks, non-reusable catalysts and poor downstream purification method have inevitably caused an expensive final product and costly wastewater treatment (Shu et al., 2010).

The economics of biodiesel production is strongly linked to feedstock cost, catalyst cost and wastewater treatment (Kastner et al., 2012). It has been estimated that 95% of global biofuel production uses edible oil as feedstocks (Sanjid et al., 2016). As a consequence, competition between energy markets with food sectors has caused the increase of edible oil prices. In biodiesel production itself, approximately 70 to 90% of overall biodiesel production cost was accounted solely for feedstock expenditure (Farooq et al., 2013). Therefore, employing cheap raw material in biodiesel production such as waste cooking oil (WCO) is a better option. Utilization of WCO in biodiesel production reduced the cost of production down to 60% in comparison to high-grade

© COPYRIG

HT UPM

2

vegetable oil consumption (Talebian-Kiakalaieh et al., 2013). Due to lack of disposal policy and inefficient waste management, WCO has been directly dumped into sewer and the environment, which led to pipeline blockage and pollution (Mara & Alam, 2008). On top of that, due to its cheap price, some unregulated industries have made profit out of recycling this waste by blending into a new cooking oil product. Thus, based on these issues, it is beneficial to employ WCO as feedstock for biodiesel production.

Transesterification is a process that is involved in biodiesel conversion by detaching 3 free fatty acids (FFA) from a molecule of triglyceride and combining them with alkyl group to form alkyl ester molecules (Sharma et al., 2011). In this process, a homogenous base catalyst, such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), was commonly being used due to its cheap price and high in reactivity (Tariq et al., 2012). Recently, carbon based catalyst has gained attention due to its reusability and high catalytic activity (Konwar et al., 2014). Previously, the development was focused on solid acid catalyst. Nevertheless, since implementation of acid-catalysed reaction was usually associated with impractical procedures such as long reaction time, high amount of alcohol usage, and high temperature condition, solid base catalyst is used due to its benefits such as higher reaction yield, short reaction period, less alcohol usage and conducted at mild reaction condition (Chew & Bhatia, 2008).However, these solid catalysts are expensive that leads to high price of biodiesel. Therefore, development of carbon based catalyst from agricultural waste is gaining interest among researchers due to its low-cost of production (Konwar et al., 2012).

Biodiesel purification step is important in order to improve the quality of the final fuel product in fulfilling the quality specifications standard (EN 14214). The presence of unwanted impurities in biodiesel such as free FFA, free glycerol, catalyst trace, moisture, remaining alcohol and unreacted triglycerides reduced the quality of the fuel (Ngamlerdpokin et al., 2011). Usually, water washing method was applied to purify the crude biodiesel. However, this conventional method produced wastewater at the end of the process, which has to be treated before being discharged (Atadashi et al., 2011; Enweremadu & Mbarawa, 2009). In contrast to purification method using adsorbents, no wastewater are produced and less product loss (Berrios et al., 2011). Activated carbon was recognized as the material with excellent adsorbent properties for purification (Konwar et al., 2014). According to Fadhil et al. (2012), utilization of activated carbon in biodiesel purification produced a better yield and quality compared to conventional water washing method.

Palm oil industry is one of the fast growing economic sectors in Malaysia (Alam, 2008). Increased demand on oil palm led to accumulation of huge amount of biomass waste, such as oil palm empty fruit bunch (OPEFB). As of now, OPEFB was either applied at the plantation as compost fertilizer, burned illegally or act as fuel to generate steam at the mill. Since it was fibrous in structure, this material was considered good for high surface area activated carbon production (Tan et al., 2009).

© COPYRIG

HT UPM

3

The overall objective of this research is to produce heterogeneous catalyst andadsorbent from oil palm biomass for biodiesel production from waste cooking oil. This research also targeted to improve the biodiesel production and purification process in comparison to conventional methods.

1.3 Specific Objectives

1) To produce activated carbon from empty fruit bunch (OPEFB) via two-steps carbonization and chemical activation method.

2) To develop and optimize carbon-supported potassium phosphate tri-basic (K3PO4/AC) catalyst for biodiesel production from WCO.

3) To purify and compare the quality of WCO-derived biodiesel using biomass-derived adsorbent with other purification methods.

1.4 Experimental overview

The overall experimental overview is shown in Figure 1.1. The first objective is on the development of K3PO4/AC catalyst for biodiesel production from waste cooking oil. By using OPEFB as raw material, the catalyst was developed through the process of carbonization, KOH-activation and K3PO4 calcination, consecutively. Subsequently, the prepared K3PO4/AC catalyst was characterized in order to study its physicochemical properties. In transesterification of WCO, the variables affecting the process were optimized in order to determine the highest biodiesel yield. The efficiency of the developed catalyst was also evaluated by conducting reusability and leaching test.

The second objective is to exploit the feasibility of the activated carbon produced from OPEFB biomass in purifying the biodiesel produced from WCO. The quality of the purified biodiesel using the activated carbon was analysed and compared with the conventional water washing method and other commercial adsorbents such as bentonite, silica gel and talc.

© COP

UPM

4

Figure 1.1: Research work flow

Objective 1

Objective 2

© COPYRIG

HT UPM

75

REFERENCES

Adam, I. K., Galadima, A., & Muhammad, A. I. (2011). Biofuels in the quest for sustainable energy development. Journal of Sustainable Development, 4(3), 10–19.

Alabarse, F. G., Conceição, R. V., Balzaretti, N. M., Schenato, F., & Xavier, A. M. (2011). In-situ FTIR analyses of bentonite under high-pressure. Applied Clay Science, 51(1–2), 202–208.

Alam, M. (2008). Production of activated carbon from oil palm empty fruit bunches for removal of zinc. Twelfth International Water Technology Conference, 373–383.

Alam, M., Muyibi, A., & Kamaldin, N. (2008). Production of activated carbon from oil palm empty fruit bunches for removal of zinc. Twelfth International Water Technology Conference, 373–383.

Alam, M. Z., Muyibi, S. A., Mansor, M. F., & Wahid, R. (2007). Activated carbons derived from oil palm empty-fruit bunches: Application to environmental problems. Journal of Environmental Sciences, 19(1), 103–108.

Alamu, O. J., Waheed, M. a., & Jekayinfa, S. O. (2008). Effect of ethanol–palm kernel oil ratio on alkali-catalyzed biodiesel yield. Fuel, 87(8–9), 1529–1533.

Alcantara, R., Amores, J., Canoira, L., Fidalgo, E., Franco, M. J., & Navarro, A. (2000). Catalytic production of biodiesel from soy-bean oil , used frying oil and tallow. Biomass and Bioenergy, 18(6), 515–527.

Alkhatib, M. F., Muyibi, S. a., & Amode, J. O. (2011). Optimization of activated carbon production from empty fruit bunch fibers in one-step steam pyrolysis for cadmium removal from aqueous solution. The Environmentalist, 31(4), 349–357.

Animal and vegetable fats and oils -- Preparation of methyl esters of fatty acids. ISO 5509:2000. Retrieved April 24, 2017, from https://www.iso.org/standard/11560.html.

Atabani, a. E., Silitonga, A. S., & Ong, H. C. (2013). edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance and emissions production. Renewable and Sustainable Energy Reviews, 18, 211–245.

Atadashi, I. M. (2014). Purification of crude biodiesel using dry washing and membrane technologies. Alexandria Engineering Journal, 54(4), 1265–1272.

Atadashi, I. M., Aroua, M. K., Abdul Aziz, a. R., & Sulaiman, N. M. N. (2012a). Production of biodiesel using high free fatty acid feedstocks. Renewable and Sustainable Energy Reviews, 16(5), 3275–3285.

© COPYRIG

HT UPM

76

Atadashi, I. M., Aroua, M. K., Abdul Aziz, a. R., & Sulaiman, N. M. N. (2012b). The effects of water on biodiesel production and refining technologies: A review. Renewable and Sustainable Energy Reviews, 16(5), 3456–3470.

Atadashi, I. M., Aroua, M. K., & Aziz, a. A. (2010). High quality biodiesel and its diesel engine application: A review. Renewable and Sustainable Energy Reviews,14(7), 1999–2008.

Atadashi, I. M., Aroua, M. K., & Aziz, a. A. (2011). Biodiesel separation and purification: A review. Renewable Energy, 36(2), 437–443.

Automotive fuels. Fatty acid methyl esters (FAME) for diesel engines. Requirements and test methods. BS EN 14214:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030109388.

Ayari, F., Srasra, E., & Trabelsi-Ayadi, M. (2005). Characterization of bentonitic clays and their use as adsorbent. Desalination, 185(May), 391–397.

Badday, A. S., Abdullah, A. Z., & Lee, K.-T. (2014). Transesterification of crude Jatropha oil by activated carbon-supported heteropolyacid catalyst in an ultrasound-assisted reactor system. Renewable Energy, 62, 10–17.

Baroutian, S., Aroua, M. K., Raman, A. A. a, & Sulaiman, N. M. N. (2011). A packed bed membrane reactor for production of biodiesel using activated carbon supported catalyst. Bioresource technology, 102(2), 1095–102.

Berrios, M., Gutiérrez, M. C., Martín, M. a., & Martín, a. (2010). Obtaining biodiesel from spanish used frying oil: Issues in meeting the EN 14214 biodiesel standard. Biomass and Bioenergy, 34(3), 312–318.

Berrios, M., Martín, M. A., Chica, A. F., & Martín, A. (2011). Purification of biodiesel from used cooking oils. Applied Energy, 88(11), 3625–3631.

Berrios, M., & Skelton, R. L. (2008). Comparison of purification methods for biodiesel. Chemical Engineering Journal journal, 144, 459–465.

Boey, P. L., Maniam, G. P., & Hamid, S. A. (2011). Performance of calcium oxide as a heterogeneous catalyst in biodiesel production: A review. Chemical Engineering Journal, 168(1), 15–22.

Boocock, D. G. B., Konar, S. K., Mao, V., Lee, C., & Buligan, S. (1998). Fast formation of high-purity methyl esters from vegetable oils. Journal of the American Oil Chemists’ Society, 75(9), 1167–1172.

Borges, M. E., & Díaz, L. (2012). Recent developments on heterogeneous catalysts for biodiesel production by oil esterification and transesterification reactions: A review. Renewable and Sustainable Energy Reviews, 16(5), 2839–2849.

Borges, M. E., Díaz, L., Alvarez-Galván, M. C., & Brito, A. (2011). High performance heterogeneous catalyst for biodiesel production from vegetal and waste oil at low temperature. Applied Catalysis B: Environmental, 102(1–2), 310–315.

© COPYRIG

HT UPM

77

Bouaid, A., Diaz, Y., Martinez, M., & Aracil, J. (2005). Pilot plant studies of biodiesel production using Brassica carinata as raw material. Catalysis Today, 106(1–4), 193–196.

Bouaid, A., Vázquez, R., Martinez, M., & Aracil, J. (2016). Effect of free fatty acids contents on biodiesel quality. Pilot plant studies. Fuel, 174, 54–62.

Canakci, M. (2007). The potential of restaurant waste lipids as biodiesel feedstocks. Bioresource technology, 98(1), 183–90.

Canakci, M., & Sanli, H. (2008). Biodiesel production from various feedstocks and their effects on the fuel properties. Journal of industrial microbiology &biotechnology, 35(5), 431–41.

Cao, F., Chen, Y., Zhai, F., & Li, J. (2008). Biodiesel production from high acid value waste frying oil catalyzed by superacid heteropolyacid. Biotechnology and Bioengineering, 101(1), 93–100.

Casas, A., Fernández, C. M., Ramos, M. J., Pérez, Á., & Rodríguez, J. F. (2010). Optimization of the reaction parameters for fast pseudo single-phase transesterification of sunflower oil. Fuel, 89(3), 650–658.

Celiktas, M. S., Sevgili, T., & Kocar, G. (2009). A snapshot of renewable energy research in Turkey. Renewable Energy, 34(6), 1479–1486.

Chew, T. L., & Bhatia, S. (2008). Catalytic processes towards the production of biofuels in a palm oil and oil palm biomass-based biorefinery. Bioresource Technology, 99(17), 7911–7922.

Chouhan, A. P. S., & Sarma, A. K. (2011). Modern heterogeneous catalysts for biodiesel production: A comprehensive review. Renewable and Sustainable Energy Reviews, 15(9), 4378–4399.

Cvengroš, J., & Cvengrošová, Z. (2004). Used frying oils and fats and their utilization in the production of methyl esters of higher fatty acids. Biomass and Bioenergy,27(2), 173–181.

Degirmenbasi, N., Boz, N., & Kalyon, D. M. (2014). Biofuel production via transesterification using sepiolite-supported alkaline catalysts. Applied Catalysis B: Environmental, 150–151, 147–156.

Dehkhoda, A. M., & Ellis, N. (2013). Biochar-based catalyst for simultaneous reactions of esterification and transesterification. Catalysis Today, 207, 86–92.

Dehkhoda, A. M., West, A. H., & Ellis, N. (2010). Biochar based solid acid catalyst for biodiesel production. Applied Catalysis A: General, 382(2), 197–204.

Demirbas, A. (2009a). Progress and recent trends in biodiesel fuels. Energy Conversion and Management, 50(1), 14–34.

© COPYRIG

HT UPM

78

Demirbas, A. (2009b). Biodiesel from waste cooking oil via base-catalytic and supercritical methanol transesterification. Energy Conversion and Management,50(4), 923–927.

Dimian, A. C., & Rothenberg, G. (2016). An Effective Modular Process for Biodiesel Manufacturing Using Heterogeneous Catalysis. Catalysis Science & Technology,6(15), 6097–6108.

Endalew, A. K., Kiros, Y., & Zanzi, R. (2011). Inorganic heterogeneous catalysts for biodiesel production from vegetable oils. Biomass and Bioenergy, 35(9), 3787–3809.

Enweremadu, C. C., & Mbarawa, M. M. (2009). Technical aspects of production and analysis of biodiesel from used cooking oil—A review. Renewable and Sustainable Energy Reviews, 13(9), 2205–2224.

Escobar, J. C., Lora, E. S., Venturini, O. J., Yáñez, E. E., Castillo, E. F., & Almazan, O. (2009). Biofuels: Environment, technology and food security. Renewable and Sustainable Energy Reviews, 13(6–7), 1275–1287.

Faccini, C. S., & Aranda, S. (2011). Dry washing in biodiesel purification: a comparative study of adsorbents. Journal of Brazillian Chemical Society, 22(3), 558–563.

Fadhil, A. B., & Abdulahad, W. S. (2014). Transesterification of mustard (Brassica nigra) seed oil with ethanol: Purification of the crude ethyl ester with activated carbon produced from de-oiled cake. Energy Conversion and Management, 77,495–503.

Fadhil, A. B., Dheyab, M. M., & Abdul-Qader, A. Q. Y. (2012). Purification of biodiesel using activated carbons produced from spent tea waste. Journal of the Association of Arab Universities for Basic and Applied Sciences, 11(1), 45–49.

Farooq, M., Ramli, A., & Subbarao, D. (2013). Biodiesel production from waste cooking oil using bifunctional heterogeneous solid catalysts. Journal of Cleaner Production, 59, 131–140.

Fat and oil derivatives. Fatty acid methyl esters (FAME). Determination of acid value. EN14104:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030084474.

Fat and oil derivatives - Fatty Acid Methyl Esters (FAME) - Determination of ester and linolenic acid methyl ester contents. BS EN 14103:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030006707.

Fat and oil derivatives. Fatty acid methyl esters (FAME). Determination of free and total glycerol and mono-, di-, triglyceride contents. EN14105:2011. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030207064.

© COPYRIG

HT UPM

79

Fat and oil derivatives. Fatty acid methyl esters (FAME). Determination of methanol content. EN14110:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030084512.

Fat and oil derivatives - Fatty acid methyl esters (FAME) - Determination of phosphorus content by inductively coupled plasma (ICP) Emission Spectrometry. BS EN 14109:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030084503.

Fat and oil derivatives - Fatty acid methyl esters (FAME) - Determination of potassium content by atomic absorption spectrometry. BS EN 14107:2003. Retrieved April 24, 2017, from http://shop.bsigroup.com/ProductDetail/?pid=000000000030084503.

Felizardo, P., Correia, M. J. N., Raposo, I., Mendes, J. F., Berkemeier, R., & Bordado, J. M. (2006). Production of biodiesel from waste frying oils. Waste management (New York, N.Y.), 26(5), 487–94.

Foo, K. Y., & Hameed, B. H. (2009). Utilization of biodiesel waste as a renewable resource for activated carbon: Application to environmental problems. Renewable and Sustainable Energy Reviews, 13(9), 2495–2504.

Free Fatty Acids in Crude and Refined Fats and Oils. AOCS Official Method Ca 5a-40:1997. Retrieved April 24, 2017, from https://aocs.personifycloud.com/PersonifyEbusiness/Store/ProductDetails?productId=111480.

Fukuda, H., Kondo, A., & Noda, H. (2001). Biodiesel fuel production by transesterification of oils. Journal of bioscience and bioengineering, 92(5), 405–16.

Gerpen, J. Van. (2005). Biodiesel processing and production. Fuel Processing Technology, 86(10), 1097–1107.

Ghadge, S. V., & Raheman, H. (2005). Biodiesel production from mahua (Madhuca indica) oil having high free fatty acids. Biomass and Bioenergy, 28(6), 601–605.

Ghadge, S. V., & Raheman, H. (2006). Process optimization for biodiesel production from mahua (Madhuca indica) oil using response surface methodology. Bioresource technology, 97(3), 379–84.

Gomes, M. G., Santos, D. Q., De Morais, L. C., & Pasquini, D. (2015). Purification of biodiesel by dry washing, employing starch and cellulose as natural adsorbents. Fuel, 155, 1–6.

Graboski, M. S., & McCormick, R. L. (1998). Combustion of fat and vegetable oil derived fuels in diesel engines. Progress in Energy and Combustion Science,24(2), 125–164.

© COPYRIG

HT UPM

80

Guan, G., Kusakabe, K., & Yamasaki, S. (2009). Tri-potassium phosphate as a solid catalyst for biodiesel production from waste cooking oil. Fuel Processing Technology, 90(4), 520–524.

Guo, F., Peng, Z.-G., Dai, J.-Y., & Xiu, Z.-L. (2010). Calcined sodium silicate as solid base catalyst for biodiesel production. Fuel Processing Technology, 91(3), 322–328.

Haas, M. J. (2005). Improving the economics of biodiesel production through the use of low value lipids as feedstocks: vegetable oil soapstock. Fuel Processing Technology, 86(10), 1087–1096.

Haas, M. J., McAloon, A. J., Yee, W. C., & Foglia, T. A. (2006). A process model to estimate biodiesel production costs. Bioresource technology, 97(4), 671–8.

Hameed, B. H., Tan, I. A. W., & Ahmad, A. L. (2009). Preparation of oil palm empty fruit bunch-based activated carbon for removal of 2,4,6-trichlorophenol: optimization using response surface methodology. Journal of hazardous materials, 164(2–3), 1316–24.

Hayyan, A., Alam, M. Z., Mirghani, M. E. S., Kabbashi, N. A., Hakimi, N. I. N. M., Siran, Y. M., & Tahiruddin, S. (2010). Sludge palm oil as a renewable raw material for biodiesel production by two-step processes. Bioresource technology,101(20), 7804–11.

Helwani, Z., Othman, M. R., Aziz, N., Fernando, W. J. N., & Kim, J. (2009). Technologies for production of biodiesel focusing on green catalytic techniques: A review. Fuel Processing Technology, 90(12), 1502–1514.

Helwani, Z., Othman, M. R., Aziz, N., Kim, J., & Fernando, W. J. N. (2009). Solid heterogeneous catalysts for transesterification of triglycerides with methanol: A review. Applied Catalysis A: General, 363(1–2), 1–10.

Hinton, A., & Ingram, K. D. (2005). Microbicidal Activity of Tripotassium Phosphate and Fatty Acids toward Spoilage and Pathogenic Bacteria Associated with Poultry. Journal of food protection, 68(7), 1462–1466.

Hor, K. Y., Chee, J. M. C., Chong, M. N., Jin, B., Saint, C., Poh, P. E., & Aryal, R. (2016). Evaluation of physicochemical methods in enhancing the adsorption performance of natural zeolite as low-cost adsorbent of methylene blue dye from wastewater. Journal of Cleaner Production, 118, 197–209.

Huynh, L., Kasim, N. S., & Ju, Y. (2011). Chapter 16 - Biodiesel production from waste oils. In Biofuels (1st ed., pp. 375–396). Elsevier.

Iakovleva, E., Maydannik, P., Ivanova, T. V., Sillanpää, M., Tang, W. Z., Mäkilä, E., Salonen, J., Gubal, A. R., Ganeev, A. A., Kamwilaisak, K., Wang, S. (2016). Modified and unmodified low-cost iron-containing solid wastes as adsorbents for efficient removal of As(III) and As(V) from mine water. Journal of Cleaner Production, 133, 1095–1104.

© COPYRIG

HT UPM

81

Islam, A., Taufiq-Yap, Y., & Chu, C. (2012). Studies on design of heterogeneous catalysts for biodiesel production. Process Safety and Environmental Protection,91(1–2), 131–144.

Jackson, N., Mcmullan, B., & Walker, L. (2014). Food additives. Self Nutrition Data,7–8. Retrieved from http://nutritiondata.self.com/topics/food-additives

Kansedo, J., Lee, K. T., & Bhatia, S. (2009). Biodiesel production from palm oil via heterogeneous transesterification. Biomass and Bioenergy, 33(2), 271–276.

Karaçetin, G., Sivrikaya, S., & Imamoğlu, M. (2014). Adsorption of methylene blue from aqueous solutions by activated carbon prepared from hazelnut husk using zinc chloride. Journal of Analytical and Applied Pyrolysis, 110, 270–276.

Karnasuta, S., & Punsuvon, V. (2007). Optimization of biodiesel production from trap grease via two-step catalyzed process. Asian Journal on Energy and Environment,8(3), 145–168.

Kasmin, H., Awang, R., & Lazim, A. M. (2015). Effect of different sterilization methods on the extracted oil from oil palm fruit, 19(1), 244–250.

Kastner, J., Miller, J., Geller, D., & Locklin, J. (2012). Catalytic esterification of fatty acids using solid acid catalysts generated from biochar and activated carbon. Catalysis Today, 190(1), 122–132.

Kim, W., Kim, M., Kim, J., & Seo, G. (2003). Dispersion measurement of heteropoly acid supported on KIT-1 mesoporous material. Microporous and mesoporous materials, 57(2), 113–120. Retrieved from http://linkinghub.elsevier.com/retrieve/pii/S1387181102005474

Kiss, A. A., Dimian, A. C., & Rothenberg, G. (2006). Solid Acid Catalysts for Biodiesel Production – Towards Sustainable Energy. Advanced Synthesis & Catalysis, 348(1–2), 75–81.

Klemeš, J., Ng, W. P. Q., Lam, H. L., Ng, F. Y., Kamal, M., & Lim, J. H. E. (2012). Waste-to-wealth: green potential from palm biomass in Malaysia. Journal of Cleaner Production, 34, 57–65.

Knothe, G., & Steidley, K. (2009). A comparison of used cooking oils: a very heterogeneous feedstock for biodiesel. Bioresource technology, 100(23), 5796–801.

Kondamudi, N., Mohapatra, S. K., & Misra, M. (2011). Quintinite as a bifunctional heterogeneous catalyst for biodiesel synthesis. Applied Catalysis A: General,393(1–2), 36–43.

Konwar, L., Chutia, S., & Boro, J. (2012). Biochar supported Cao as heterogeneous catalyst for biodiesel production. International Journal of Innovative Research and Development, 186–195.

© COPYRIG

HT UPM

82

Konwar, Boro, J., & Deka, D. (2014). Review on latest developments in biodiesel production using carbon-based catalysts. Renewable and Sustainable Energy Reviews, 29, 546–564.

Kumari, A., Mahapatra, P., Garlapati, V. K., & Banerjee, R. (2009). Enzymatic transesterification of Jatropha oil. Biotechnology for biofuels, 2(1), 1.

Lam, M. K., Lee, K. T., & Mohamed, A. R. (2010). Homogeneous, heterogeneous and enzymatic catalysis for transesterification of high free fatty acid oil (waste cooking oil) to biodiesel: a review. Biotechnology advances, 28(4), 500–18.

Lang, X., Dalai, a K., Bakhshi, N. N., Reaney, M. J., & Hertz, P. B. (2001). Preparation and characterization of bio-diesels from various bio-oils. Bioresource technology, 80(1), 53–62.

Lee, H. V., Taufiq-Yap, Y. H., Hussein, M. Z., & Yunus, R. (2013). Transesterification of jatropha oil with methanol over Mg-Zn mixed metal oxide catalysts. Energy,49, 12–18.

Lee, Zubir, Z. A., Jamil, F. M., Matsumoto, A., & Yeoh, F. Y. (2014). Combustion and pyrolysis of activated carbon fibre from oil palm empty fruit bunch fibre assisted through chemical activation with acid treatment. Journal of Analytical and Applied Pyrolysis, 110, 408–418.

Leung, D. Y. C., & Guo, Y. (2006). Transesterification of neat and used frying oil: Optimization for biodiesel production. Fuel Processing Technology, 87(10), 883–890.

Leung, D. Y. C., Wu, X., & Leung, M. K. H. (2010). A review on biodiesel production using catalyzed transesterification. Applied Energy, 87(4), 1083–1095.

Liu, S., McDonald, T., & Wang, Y. (2010). Producing biodiesel from high free fatty acids waste cooking oil assisted by radio frequency heating. Fuel, 89(10), 2735–2740.

Lokman, I. M., Rashid, U., Zainal, Z., Yunus, R., & Taufiq-Yap, Y. H. (2014). Microwave-assisted biodiesel production by esterification of palm fatty acid distillate. Journal of Oleo Science, 63(9), 849–855.

Lokman, I. M., Rashid, U., & Taufiq-Yap, Y. H. (2015a). Microwave-Assisted Methyl Ester Production from Palm Fatty Acid Distillate over a Heterogeneous Carbon-Based Solid Acid Catalyst. Chemical Engineering and Technology, 38(10), 1837–1844.

Lokman, I. M., Rashid, U., Taufiq-Yap, Y. H., & Yunus, R. (2015b). Methyl ester production from palm fatty acid distillate using sulfonated glucose-derived acid catalyst. Renewable Energy, 81, 347–354.

Lokman, I. M., Rashid, U., & Taufiq-Yap, Y. H. (2016). Meso- and macroporous sulfonated starch solid acid catalyst for esterification of palm fatty acid distillate. Arabian Journal of Chemistry, (2), 179–189.

© COPYRIG

HT UPM

83

Lotero, E., Liu, Y., Lopez, D. E., Suwannakarn, K., Bruce, D. a., & Goodwin, J. G. (2005). Synthesis of biodiesel via acid catalysis. Industrial & Engineering Chemistry Research, 44(14), 5353–5363.

Lou, W. Y., Zong, M. H., & Duan, Z. Q. (2008). Efficient production of biodiesel from high free fatty acid-containing waste oils using various carbohydrate-derived solid acid catalysts. Bioresource technology, 99(18), 8752–8.

Lubelli, B., de Winter, D. A. M., Post, J. A., van Hees, R. P. J., & Drury, M. R. (2013). Cryo-FIB-SEM and MIP study of porosity and pore size distribution of bentonite and kaolin at different moisture contents. Applied Clay Science, 80–81, 358–365.

Ma, F., & Hanna, M. (1999). Biodiesel production: a review. Bioresource technology,70, 1–15.

Mahajan, S., Konar, S. K., & Boocock, D. G. B. (2006). Standard biodiesel from soybean oil by a single chemical reaction. Journal of the American Oil Chemists’ Society, 83(7), 641–644.

Mara, U. T., & Alam, S. (2008). Analysis of waste cooking oil as raw material for biofuel production. Global Journal of Environmental Research, 2(2), 81–83.

Marchetti, J. M. (2012). A summary of the available technologies for biodiesel production based on a comparison of different feedstock’s properties. Process Safety and Environmental Protection, 90(3), 157–163.

Marzbani, P., Resalati, H., Ghasemian, A., & Shakeri, A. (2013). Talc , a multi-purpose filler : A review of talc’s features and improvement methods of its efficiency. Scholars Research Library, 4(6), 159–162.

Mat, R., & Samsudin, R. (2012). Solid catalysts and theirs application in biodiesel production. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2), 142–149.

Miller, F. a., & Wilkins, C. H. (1952). Infrared spectra and characteristic frequencies of inorganic ions. Analytical Chemistry, 24(8), 1253–1294.

Mittelbach, M., & Enzelsberger, H. (1999). Transesterification of heated rapeseed oil for extending diesel fuel. Journal of the American Oil Chemists’ Society, 76(5), 545–550.

MPOB p2.1:2004. Rukunudin, I.H., White, P.J., Bern, C.J., Bailey, T.B., 1998. A modified method for determining free fatty acids from small soybean oil sample sizes. J. Am. Oil Chem. Soc. 75, 563–568.

Mun, L. K., Aziz, N. A., & Cocchi, M. (2012). Malaysia’s Biomass Potential. BESustainable, (April), 33–36. Retrieved from http://www.besustainablemagazine.com/cms2/malaysias-biomass-potential/

© COPYRIG

HT UPM

84

Ngamlerdpokin, K., Kumjadpai, S., Chatanon, P., Tungmanee, U., Chuenchuanchom, S., Jaruwat, P., Lertsathitphongs, P., Hunsom, M. (2011). Remediation of biodiesel wastewater by chemical- and electro-coagulation: a comparative study. Journal of environmental management, 92(10), 2454–60.

Nye, M. J., Wllliamson, T. W., Deshpande, S., Schrader, J. H., Snively, W. H., & French, C. L. (1983). Conversion of used frying oil to diesel fuel by transesterification : preliminary tests. Journal of the American Oil Chemists’ Society, 60(8), 1598–1601.

Omar, R., Idris, A., Yunus, R., Khalid, K., & Aida Isma, M. I. (2011). Characterization of empty fruit bunch for microwave-assisted pyrolysis. Fuel, 90(4), 1536–1544.

Ooi, C., Ang, C., & Yeoh, F. (2013). The properties of activated carbon fiber derived from direct activation from oil palm empty fruit bunch fiber. Advanced Materials Research, 686, 109–117.

Ossman, M. E., Abdel Fatah, M., & Taha, N. A. (2013). Fe(III) removal by activated carbon produced from Egyptian rice straw by chemical activation. Desalination and Water Treatment, 52(April 2016), 3159–3168.

Peng, B. X., Shu, Q., Wang, J. F., Wang, G. R., Wang, D. Z., & Han, M. H. (2008). Biodiesel production from waste oil feedstocks by solid acid catalysis. Process Safety and Environmental Protection, 86(6), 441–447.

Petroleum products - Determination of water - Coulometric Karl Fischer titration method, EN ISO 12937:2000. Retrieved April 24, 2017, from https://www.iso.org/standard/2730.html.

Pinto, A. C., Guarieiro, L. L. N., Rezende, M. J. C., Ribeiro, N. M., & Ednildo, A. (2005). Biodiesel : An Overview. Journal of the Brazilian Chemical Society,16(6B), 1313–1330.

Predojević, Z. J. (2008). The production of biodiesel from waste frying oils: A comparison of different purification steps. Fuel, 87(17–18), 3522–3528.

Puna, J. F., Gomes, J. F., Correia, M. J. N., Soares Dias, A. P., & Bordado, J. C. (2010). Advances on the development of novel heterogeneous catalysts for transesterification of triglycerides in biodiesel. Fuel, 89(11), 3602–3606.

Rafatullah, M., Sulaiman, O., Hashim, R., & Ahmad, A. (2010). Adsorption of methylene blue on low-cost adsorbents: A review. Journal of Hazardous Materials, 177(1–3), 70–80.

Ramadhas, a, Jayaraj, S., & Muraleedharan, C. (2005). Biodiesel production from high FFA rubber seed oil. Fuel, 84(4), 335–340.

Ramos, M. J., Fernandez, C. M., Casas, A., Rodriguez, L., & Perez, A. (2009). Influence of fatty acid composition of raw materials on biodiesel properties. Bioresource Technology, 100(1), 261–268.

© COPYRIG

HT UPM

85

Sabudak, T., & Yildiz, M. (2010). Biodiesel production from waste frying oils and its quality control. Waste management (New York, N.Y.), 30(5), 799–803.

Sandoval, R., Cooper, A. M., Aymar, K., Jain, A., & Hristovski, K. (2011). Removal of arsenic and methylene blue from water by granular activated carbon media impregnated with zirconium dioxide nanoparticles. Journal of hazardous materials, 193, 296–303.

Sanjid, A., Kalam, M. A., Masjuki, H. H., Varman, M., Zulkifli, N. W. B. M., & Abedin, M. J. (2016). Performance and emission of multi-cylinder diesel engine using biodiesel blends obtained from mixed inedible feedstocks. Journal of Cleaner Production, 112, 4114–4122.

Semwal, S., Arora, A. K., Badoni, R. P., & Tuli, D. K. (2011). Biodiesel production using heterogeneous catalysts. Bioresource technology, 102(3), 2151–61.

Shahryari, Z., Goharrizi, A. S., & Azadi, M. (2010). Experimental study of methylene blue adsorption from aqueous solutions onto carbon nano tubes. International Journal of Water Resources and Environmental Engineering, 2(2), 16–28.

Sharma, Y. C., Singh, B., & Korstad, J. (2011). Latest developments on application of heterogenous basic catalysts for an efficient and eco friendly synthesis of biodiesel: A review. Fuel, 90(4), 1309–1324.

Sharma, Y. C., Singh, B., & Upadhyay, S. N. (2008). Advancements in development and characterization of biodiesel: a review. Fuel, 87(12), 2355–2373.

Shu, Q., Gao, J., Nawaz, Z., Liao, Y., Wang, D., & Wang, J. (2010). Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid acid catalyst. Applied Energy, 87(8), 2589–2596.

Shuit, S. H., Tan, K. T., Lee, K. T., & Kamaruddin, A. H. (2009). Oil palm biomass as a sustainable energy source: A Malaysian case study. Energy, 34(9), 1225–1235.

Standard Specification for Biodiesel Fuel (B100) Blend Stock for Distillate Fuels. ASTM D6751 – 03. Retrieved April 24, 2017, from https://www.astm.org/DATABASE.CART/HISTORICAL/D6751-03.htm.

Suwannakarn, K., Lotero, E., Ngaosuwan, K., & Goodwin, J. G. (2009). Simultaneous free fatty acid esterification and triglyceride transesterification using a solid acid catalyst with in situ removal of water and unreacted methanol. Industrial & Engineering Chemistry Research, 48(6), 2810–2818.

Takahashi, R., Nakanishi, K., & Soga, N. (1995). Effects of aging and solvent exchange on pore structure of silica gels with interconnected macropores. Journal of Non-Crystalline Solids, 189, 66–76.

Talebian-Kiakalaieh, A., Amin, N. A. S., & Mazaheri, H. (2013). A review on novel processes of biodiesel production from waste cooking oil. Applied Energy, 104,683–710.

© COPYRIG

HT UPM

86

Tan, I. A. W., Ahmad, A. L., & Hameed, B. H. (2009). Adsorption isotherms, kinetics, thermodynamics and desorption studies of 2,4,6-trichlorophenol on oil palm empty fruit bunch-based activated carbon. Journal of Hazardous Materials,164(2), 473–482.

Tao, J., & Rappe, A. M. (2014). Physical adsorption: Theory of van der Waals interactions between particles and clean surfaces. Physical Review Letters,112(March), 1–5.

Tariq, M., Ali, S., & Khalid, N. (2012). Activity of homogeneous and heterogeneous catalysts, spectroscopic and chromatographic characterization of biodiesel: A review. Renewable and Sustainable Energy Reviews, 16(8), 6303–6316.

Thanh, L. T., Okitsu, K., Sadanaga, Y., Takenaka, N., Maeda, Y., & Bandow, H. (2010). A two-step continuous ultrasound assisted production of biodiesel fuel from waste cooking oils: a practical and economical approach to produce high quality biodiesel fuel. Bioresource technology, 101(14), 5394–401.

Thanh, L. T., Okitsu, K., Sadanaga, Y., Takenaka, N., Maeda, Y., & Bandow, H. (2013). A new co-solvent method for the green production of biodiesel fuel –Optimization and practical application. Fuel, 103, 742–748.

Valdes, H., Sanchez-Polo, M., Rivera-Utrilla, J., & Zaror, C. a. (2002). Effect of ozone treatment on surface properties of activated carbon. Langmuir, 18(6), 2111–2116.

Veljković, V. B., Banković-Ilić, I. B., & Stamenković, O. S. (2015). Purification of crude biodiesel obtained by heterogeneously-catalyzed transesterification. Renewable and Sustainable Energy Reviews, 49, 500–516.

Vicente, G., Martínez, M., & Aracil, J. (2004). Integrated biodiesel production: a comparison of different homogeneous catalysts systems. Bioresource technology,92(3), 297–305.

Vijayalakshmi, U. (2005). Synthesis and characterization of porous silica gels for biomedical applications. Trends Biomaterial and Artificial Organs, 18(January), 101–105.

Wang, Y., Ma, S., Zhao, M., Kuang, L., Nie, J., & Riley, W. W. (2011). Improving the cold flow properties of biodiesel from waste cooking oil by surfactants and detergent fractionation. Fuel, 90(3), 1036–1040.

Wen, Z., Yu, X., Tu, S. T., Yan, J., & Dahlquist, E. (2010). Synthesis of biodiesel from vegetable oil with methanol catalyzed by Li-doped magnesium oxide catalysts. Applied Energy, 87(3), 743–748.

Xu, Y. J., Li, G. X., & Sun, Z. Y. (2016). Development of biodiesel industry in China: Upon the terms of production and consumption. Renewable and Sustainable Energy Reviews, 54, 318–330.

© COPYRIG

HT UPM

87

Yaakob, Z., Mohammad, M., & Alherbawi, M. (2013). Overview of the production of biodiesel from Waste cooking oil. Renewable and Sustainable Energy Reviews,18, 184–193.

Yaakob, Z., Sukma, I., Sukarman, B., Narayanan, B., Rozaimah, S., & Abdullah, S. (2012). Utilization of palm empty fruit bunch for the production of biodiesel from Jatropha curcas oil. Bioresource Technology, 104, 695–700.

Yee, K. F., Kansedo, J., & Lee, K. T. (2010). Biodiesel Production From Palm Oil Via Heterogeneous Transesterification: Optimization Study. Chemical Engineering Communications, 197(12), 1597–1611.

Yusuf, N. N. a. N., Kamarudin, S. K., & Yaakub, Z. (2011). Overview on the current trends in biodiesel production. Energy conversion and management, 52(7), 2741–2751.

Zabeti, M., Wan Daud, W. M. A., & Aroua, M. K. (2009). Activity of solid catalysts for biodiesel production: A review. Fuel Processing Technology, 90(6), 770–777.

Zah, R., & Ruddy, T. (2009). International trade in biofuels: an introduction to the special issue. Journal of Cleaner Production, 17, S1–S3.

Zhang, K., Nalaparaju, A., Chen, Y., & Jiang, J. (2014). Biofuel purification in zeolitic imidazolate frameworks: the significant role of functional groups. Physical chemistry chemical physics, 16(20), 9643–55.

Zhang, Y., Dubé, M. a., McLean, D. D., & Kates, M. (2003). Biodiesel production from waste cooking oil: 1. Process design and technological assessment. Bioresource Technology, 89(1), 1–16.

Zullaikah, S., Lai, C. C., Vali, S. R., & Ju, Y. H. (2005). A two-step acid-catalyzed process for the production of biodiesel from rice bran oil. Bioresource technology,96(17), 1889–1896.